This one is "on" your travel agent.
If there is a cabin available in the EXACT same category, the cabin can be changed. Go online. Look at the cruise you are on and see if there are any cabins in the EXACT category. E.G., 2E. Find an acceptable cabin, call your TA back, and insist that they call RC and change the cabin.
(ETA: If your agent refuses, you are SOL, because RC won't talk to you once you have a TA. They own your reservation.)